Of Maybugs and Men: A History and Philosophy of the Sciences of Homosexuality

By Pieter R. Adriaens and Andreas De Block

A much-needed exploration of the history and philosophy of scientific research into male homosexuality.

Questions about the naturalness or unnaturalness of homosexuality are as old as the hills, and the answers have often been used to condemn homosexuals, their behaviors, and their relationships. In the past two centuries, a number of sciences have involved themselves in this debate, introducing new vocabularies, theories, arguments, and data, many of which have gradually helped tip the balance toward tolerance and even acceptance. In this book, philosophers Pieter R. Adriaens and Andreas De Block explore the history and philosophy of the gay sciences, revealing how individual and societal values have colored how we think about homosexuality.

The authors unpack the entanglement of facts and values in studies of male homosexuality across the natural and human sciences and consider the extent to which science has mitigated or reinforced homonegative mores. The focus of the book is on homosexuality’s assumed naturalness. Geneticists rephrased naturalness as innateness, claiming that homosexuality is innate—colloquially, that homosexuals are born gay. Zoologists thought it a natural affair, documenting its existence in myriad animal species, from maybugs to men. Evolutionists presented homosexuality as the product of natural selection and speculated about its adaptive value. Finally, psychiatrists, who initially pathologized homosexuality, eventually appealed to its naturalness or innateness to normalize it. 

Discussing findings from an array of sciences—comparative zoology, psychiatry, anthropology, evolutionary biology, social psychology, developmental biology, and machine learning—this book is essential reading for anyone interested in what science has to say about homosexuality.

• Language: English
• Publisher: University of Chicago Press
• Release date: Dec 21, 2022
• ISBN: 9780226822433

Book preview

Cover Page for Of Maybugs and Men

Of Maybugs and Men

Of Maybugs and Men

A History and Philosophy of the Sciences of Homosexuality

Pieter R. Adriaens and Andreas De Block

The University of Chicago Press

Chicago and London

The University of Chicago Press, Chicago 60637

The University of Chicago Press, Ltd., London

© 2022 by The University of Chicago

All rights reserved. No part of this book may be used or reproduced in any manner whatsoever without written permission, except in the case of brief quotations in critical articles and reviews. For more information, contact the University of Chicago Press, 1427 E. 60th St., Chicago, IL 60637.

Published 2022

Printed in the United States of America

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ISBN-13: 978-0-226-82242-6 (cloth)

ISBN-13: 978-0-226-82244-0 (paper)

ISBN-13: 978-0-226-82243-3 (e-book)

DOI: https://doi.org/10.7208/chicago/9780226822433.001.0001

Published with the support of the Belgian University Foundation.

Library of Congress Cataloging-in-Publication Data

Names: Adriaens, Pieter R., author. | Block, Andreas de, author.

Title: Of maybugs and men : a history and philosophy of the sciences of homosexuality / Pieter R. Adriaens and Andreas De Block.

Other titles: History and philosophy of the sciences of homosexuality

Description: Chicago ; London : The University of Chicago Press, 2022. | Includes bibliographical references and index.

Identifiers: LCCN 2022022554 | ISBN 9780226822426 (cloth) | ISBN 9780226822440 (paperback) | ISBN 9780226822433 (ebook)

Subjects: LCSH: Male homosexuality—Research—History. | Male homosexuality—Research—Philosophy. | Homosexuality—Genetic aspects—Research—History. | BISAC: SOCIAL SCIENCE / LGBTQ Studies / Gay Studies | SCIENCE / Life Sciences / Biology

Classification: LCC HQ76 .A37 2022 | DDC 306.76/62—dc23/eng/20220602

LC record available at https://lccn.loc.gov/2022022554

This paper meets the requirements of ANSI/NISO Z39.48-1992 (Permanence of Paper).

For Joris and Joris, with whom it probably all began. (PRA)

Contents

Introduction: Thinking about Science and Homosexuality

CHAPTER 1  Not by Genes and Hormones Alone: On Homosexuality and Innateness

CHAPTER 2  Sham Matings and Other Shenanigans: On Animal Homosexuality

CHAPTER 3  Beyond the Paradox: On Homosexuality and Evolutionary Theory

CHAPTER 4  Values, Facts, and Disorders: On Homosexuality and Psychiatry

Epilogue: Gaydars and the Dangers of Research on Sexual Orientation

Acknowledgments

Notes

References

Index

Introduction

Thinking about Science and Homosexuality

A knowledge of the historic and philosophical background gives that kind of independence from prejudices of his generation from which most scientists are suffering.

Albert Einstein

Why do some men enjoy submitting to sex? The question would not be out of place in a contemporary science magazine (What makes people gay?), but it in fact originates with an unknown Greek philosopher from late antiquity, in a treatise (the Problemata) inspired by the Aristotelian tradition of natural philosophy.¹ (Readers will find answers to this question at the beginning of chapter 1.) The core of this tradition was to describe and explain the wide variety of natural phenomena, and for natural philosophers that variety certainly included human male homosexuality.

The ancient Greeks may have been quite casual about some homosexual activities (at least if their vases are anything to go by), but between the eleventh and the thirteenth century, when many Greek and Arabic texts, including the Problemata, were translated into Latin, sexual morality had changed dramatically. Sexual acts between men were now subsumed under the sin of sodomy and denounced by ecclesiastical and worldly authorities alike. One can only imagine, then, the reactions of late medieval readers of the Problemata, many of whom were loyal fans of Aristotle, when confronted with this time capsule’s frank questions about anal sex between men.

Thanks to historians of philosophy, we actually do know what some of them were thinking (Cadden 2001). The fourteenth-century Italian philosopher and commentator Pietro d’Abano was clearly in two minds about the Problemata’s discussion. On the one hand, he dauntlessly continued its naturalistic search for causes of male homosexuality, adding his own astrological explanations along the way. On the other, and slightly at odds with the overall evenhandedness of his comments, he appended a new and rather moralistic narrative, condemning male homosexuality as a perverse and filthy habit and abhorring the monstrous nature of homosexuals (quoted in Cadden 2001, 75–76).

D’Abano’s work can itself serve as a time capsule for contemporary commentators who, on the face of it, will perhaps find few affinities with his late medieval mindset. Over time, authority-based astrological hypotheses have given way to neurological, endocrinological, and genetic hypotheses. Moreover, d’Abano’s crude condemnation of homosexuality would seem to set him light-years apart from contemporary scientific research on the topic, which prides itself in pursuing value-free knowledge. In reality, however, the ideal of value-free science has often merely pushed moral values underground, where their effects are much harder to assess. The psychiatric history of homosexuality—the central topic of the final chapter—is a case in point. Scientific evidence may have played a role in both establishing and abandoning the view that homosexuality is a mental disorder, but so did a number of value judgments made by psychiatrists, including the judgment that heterosexuality is the sexual norm.

This book is all about the intimate engagement of facts and values in our thinking about homosexuality during the past two hundred years. More particularly, it focuses on the body of knowledge provided by a range of gay sciences scattered across various science groups, including the humanities, the social sciences, and the biomedical sciences.² Still, this is not a science book. Rather, it is a book about the history and philosophy of the gay sciences. In this introduction, we elucidate the nature and the inevitable limitations of our approach, we discuss our terminology, and we provide a brief summary of the book’s four chapters and its epilogue.

History and Philosophy of the Gay Sciences

Science produces reliable knowledge, and so twenty-first-century Westerners turn to the sciences to discover more about the nature and causes of homosexuality. We appeal to life scientists in our search for the biological controls of homosexuality; we call in psychologists to assess the well-being or social success of children raised by gay parents; we rely on historians and anthropologists to map out the sexual landscapes of earlier and non-Western societies. We trust their answers more than those provided by any other source of knowledge, including folk science, theology, or gay magazines.

Still, the gay sciences are many, and dissensus has been legion, both in the past and in the present, and both within and among disciplines. This book details a number of such disputes, and it does so by meandering between two disciplinary domains: the history of science and the philosophy of science. In this section, we consider the value and functions of both domains in turn.

Historians and philosophers of science often consider the history of science a graveyard of science (Frost-Arnold 2011, 1138) or a cemetery of theories (Stengers 2000, 31) that may have worked for a while but were then abandoned for a better alternative. Why should anyone be interested in such a cemetery? However, we agree with historians of science that their work can generally be useful in many ways (see, e.g., Chang 2017), some of which we hope to illustrate in this book.

First, a history of science perspective can help excite curiosity about the process of past scientific endeavors. How did science proceed in the past? What kinds of evidence were being considered in scientific decision-making? One wonders, for example, how psychiatrists came to consider homosexuality as a disorder rather than as a sin or a crime, which had previously been common practice. What arguments, if any, did they present to make their case? And how did they come to abandon that view again in the early 1970s?

Second, studying the history of science can improve our understanding of current scientific knowledge and practice by carefully reconstructing its historical trajectory. How did scientists come to think this way? For example, knowing how and why twentieth-century psychiatrists abandoned the disorder view of homosexuality may help us understand how their contemporary colleagues think about (historically) related conditions such as fetishism and pedophilia and why they continue to distinguish between disordered and nondisordered sexual interests.

Third, the history of science can actually improve contemporary science itself, rather than just our understanding of it, and function as what philosopher Hasok Chang (2017, 94) calls a complementary science. In that capacity, it can confront scientists with the past contingencies behind their orthodoxy,³ expose their blind spots and their indebtedness to what is now considered flawed science, and fill the gaps in their work. The success and focus of many contemporary scientists stems from their ruthless elimination of alternative questions and perspectives, some of which are perfectly scientific in themselves. For example, many contemporary biologists prefer mechanistic to mentalistic explanations of animal homosexual behaviors. They find it hard to even consider attributing these behaviors to underlying mental states, such as desires or preferences, and opt instead for explanations in terms of inabilities, unusual circumstances, and overwhelming biological imperatives. In chapter 2, we will see that the work of some nineteenth-century zoologists can help us break that trend. More generally, several chapters in this book can be read as an appeal to at least consider alternative questions and hypotheses in the gay sciences, even if they seem unconventional, outdated, or downright incongruous.

Questions about usefulness have been asked not only about the history of science but also about the philosophy of science—a second domain in which this book operates. Some scientists are very dismissive of philosophers who study their discipline. The Nobel Prize–winning physicist Richard Feynman was among them. He once allegedly quipped that the philosophy of science is as useful to scientists as ornithology is to birds.⁴ Chang (2017, 91) adds, I fear what he might have thought about the history of science, which would be more like paleontology, obsessing about extinct birds. A crash course in ornithology might indeed be very helpful to some birds, if only their brains would allow it, but that, of course, is not what Feynman meant. Rather, he meant to say that philosophers (of science) are of no use to scientists.

We disagree with Feynman, and we are not the only ones. In a recent opinion paper by Lucie Laplane et al. (2019), some philosophers and scientists teamed up to advocate the importance of the philosophy of science for the sciences. In their view, its contribution can take at least three forms.

First, philosophers have always been concerned with analyzing, clarifying, and even improving the concepts we use in various spheres of life. Some philosophers even claim that such conceptual work is the proper task of . . . philosophy (P. Strawson 1985, 23). Of course, there are scientists who are happy to perform their own conceptual work, but very often their diligence prevents them from indulging in it, and that is where philosophers of science can step in. Likewise, many chapters of this book aim to analyze and clarify the concepts used in the gay sciences, including the ideas of innateness, desire, preference, and disorder.

Second, philosophers of science critically engage with the assumptions that underlie scientific hypotheses and explanations. Much like their concepts, over time, many of the assumptions scientists build on have become so commonplace as to be virtually invisible. Philosophers of science can then alert us when these assumptions are or become problematic in the light of new scientific or philosophical developments. If it is true, for example, that many animals are capable of having mental states formerly assumed to be uniquely human, as recent philosophical work on animal minds suggests (see, e.g., Andrews 2014), then it might be time to reconsider the assumption that mechanistic explanations of homosexual behavior in animals are always superior to mentalistic explanations.

Third, philosophers of science can help foster dialogue among the sciences, another pursuit for which many scientists have neither time nor interest. Academic research today encourages specialization, and specialization can come at the expense of interdisciplinarity. In the third chapter of this book, for example, we argue that some contemporary evolutionists overestimate the importance of the particular form of homosexuality with which twenty-first-century Westerners are most familiar. In doing so, they neglect or disregard other forms of homosexuality that are extensively documented by historians and anthropologists. By bringing together insights from various disciplines in both the life sciences and the human sciences, we hope to set up new ways to research the evolution of homosexuality.⁵

The dialogue stimulated by philosophers of science benefits not only the sciences but also society. Science does not occur in a vacuum. It is as much the product of a society as it produces and molds that society. Very often, its findings impact the way we think about even the most intimate parts of our lives, including our sexuality. Traditionally, scientific findings about homosexuality have figured prominently in moral and political debates. Some years ago, for example, the author of a catalogue for a prominent exhibition on animal homosexuality noted that homosexuality is a common and widespread phenomenon in the animal world, and he expressed his hope that this finding would finally reject the all too well-known argument that homosexual behavior is a crime against nature (Søli 2009). Discussing recent work in genetics, evolutionary biologist Emmanuele A. Jannini and his colleagues (2010, 3250) offered a similar argument: These [genetic] studies suggest that the dynamics of genetic factors influencing homosexuality . . . are a natural aspect of human sexual variability. These findings further discredit the assumptions that homosexuality is pathological and that it should be cured rather than accepted and respected. Such arguments are perhaps as problematic as they are understandable. They are problematic because of their basic assumption that nature can provide us with moral guidelines—an assumption we will return to in the epilogue of this book. Still, they are understandable because scientists and science educators are human beings, and their ideas are to some extent informed by their everyday attitudes and social interactions—attitudes and interactions in which moral and other nonepistemic values play an important role.

As philosophers of science, we cherish the intricate engagement between science and values. Science is not, cannot, and should not be value-free. Its values do sometimes bias our understanding of sexuality, and we are well aware that in the past, such biases have caused a lot of misery, particularly for homosexuals. Sometimes, however, discussing values can help us get a better picture of how the world really is. Some work in feminist philosophy of science, for example, builds on the idea that the patriarchy has produced a lot of bad science, but it also acknowledges that the mistakes of the past can be corrected by incorporating a feminine perspective into science (Lloyd 2005). Similarly, some of the current sciences of sexual orientation may be more reliable because they generally build on a less negative attitude toward homosexuality than the nineteenth- or twentieth-century sciences of sexual orientation.

All in all, we believe that both the history of science and the philosophy of science can be very useful for the gay sciences. Some readers may wonder, however, why we would want to combine both disciplines. The answer is that they are complementary sciences, both in Hasok Chang’s sense that they can complement the sciences and in the sense that they can complement each other. As mentioned before, the history of science can be quite useful to various actors, and that includes philosophers of science. Only the history of science can really substantiate, corroborate, or falsify philosophical claims about the progress, utility, and the rules of the scientific game. The famous philosopher of science Imre Lakatos (1970, 91) even went so far as to say that philosophy of science without history of science is empty. Conversely, according to Lakatos, history of science without philosophy of science is blind. We always look at history from some theoretical perspective; the history of science can only increase our knowledge when we are able to recognize the relevance of historical facts.

A Love That Speaks Its Many Names

The Austro-Hungarian journalist and human rights activist Károly Kertbeny coined the word homosexuality (Homosexualität) in an 1868 private letter to his German colleague, Karl Heinrich Ulrichs, whom we will meet again later in several chapters of this book (Féray, Herzer, and Peppel 1990). Both Kertbeny and Ulrichs were active anonymously in denouncing the criminal prosecution of homosexuals under Prussian and German law, although they did so on different grounds. While Kertbeny opted for the liberal argument that the state does not have the right to meddle in sexual relationships between consenting adult partners (Takács 2004), Ulrichs advocated the naturalistic argument that homosexuality’s innateness should exempt it from punishment.

Kertbeny’s neologism homosexuality was probably connected to his activist struggle (Herzer 1986). While he never explicitly provided a reason for introducing it, his writing suggests that he considered some of the existing terminology either stigmatizing, as in the case of sodomy, pederasty, and indecency against nature (widernatürliche Unzucht), or hopelessly confused, as in the case of sexual inversion, contrary sexual feeling (konträre Sexualempfindung), and Ulrichs’s Uranism. The long-term success of Kertbeny’s term was likely due to its generality and its theory neutrality. Because homosexuality did not spring from any theory about sexuality, it readily found its place in the work of various (and even rivaling) early twentieth-century authors (Herzer 1986, 16). Moreover, following Kertbeny’s own practice, many of them quickly interpreted the term in the broadest possible sense. In his Studies in the Psychology of Sex, for example, sexologist Henry Havelock Ellis proposed to distinguish homosexuality from its various subtypes, such as (the innate) sexual inversion: Sexual inversion . . . means sexual instinct turned by inborn constitutional abnormality toward persons of the same sex. It is thus a narrower term than homosexuality, which includes all sexual attractions between persons of the same sex, even when seemingly due to the accidental absence of the natural objects of sexual attraction, a phenomenon of wide occurrence among all human races (H. Ellis 1900, 11).

In this book, we follow Kertbeny’s neutral and broad interpretation of the term homosexuality as referring to any kind of sexual state or activity, whether physical or mental, that involves or focuses on one or more persons of the same sex. One of the advantages of this thin definition is that it allows us to ascribe homosexuality to a variety of states, activities, and actors and to talk about various forms of homosexuality. When it comes to actors, our definition allows us to include nonhuman animals and individuals from non-Western or past societies, even if some of their activities markedly differ from those we typically associate with contemporary Western homosexuality. When it comes to states and activities, our definition allows us to meaningfully talk about homosexual behaviors as well as about homosexual desires, fantasies, preferences, orientations, and even identities. In chapter 2, we go to great lengths in defining and demarcating these various states and activities, examining some rather unusual combinations of actors and activities. Some philosophers and biologists firmly believe, for example, that there are no such things as homosexual desires and preferences among nonhuman animals. We will argue against this view on both conceptual and empirical grounds. As it turns out, many nonhuman animals are motivated to have sex with individuals of their own sex and hence can be said to have homosexual desires, and at least some animals prefer homosexual activities, since they choose to have sex with individuals of their own sex even when individuals of the other sex are sexually available. Whether animals can have a homosexual orientation, here defined as a stable homosexual preference, is a hotly debated matter, but we think that the evidence supports the view that such orientation can be found in at least a few species.

Finally, our definition of homosexuality is so thin that it allows us to distinguish among diverse forms of homosexuality in men, or homosexual phenotypes, three of which play quite important roles in this book. Some incarcerated men are known to engage in homosexual behaviors and to fantasize about same-sex partners, even though most of them do not identify as homosexuals, and even though they would sexually prefer female to male partners if they were given a choice. Such prison homosexuality is often described as one example of situational homosexuality (Hartenstein and Gonsiorek 2015). Another homosexual phenotype is known as modern or egalitarian homosexuality (Murray 2000). This is the form of homosexuality with which twenty-first-century Westerners are most familiar, as modern homosexuals are perhaps the most visible and vocal subgroup of all homosexuals. Modern homosexual men have sex with men because they consistently prefer homosexual to heterosexual activities, even to the point of being exclusively homosexual throughout their lives. Moreover, most of these men self-identify as homosexuals, and they often claim to have discovered their sexual orientation at an early age. Interestingly, modern homosexual partners tend to be of similar age and social status (and thus egalitarian), which distinguishes modern homosexuality from a third phenotype. In many societies, both past and present, adult men engage in sexual activities with boys and adolescents. They prefer these activities to heterosexual activities, even though society expects them to marry and have children, and even though they do not self-identify as homosexuals. This third form of homosexuality is known under many names, including transgenerational homosexuality (Stein 1999) and ritualized homosexuality (Herdt 1994).⁶

Many scientists have no trouble naming these various (combinations of) activities and states as instances of homosexuality. Kertbeny’s neologism, however, has also had its opponents, both within the (gay) scientific literature and beyond. LGBTQ studies, for example, tend to shun the term because many believe it suggests a dichotomous or binary difference between homosexuality and heterosexuality—a difference that simply does not fit with the way many people experience and understand their own sexuality (Murphy 1997). Some zoologists have suggested reserving homosexuality for human activities and replacing it in the context of animal behavior with supposedly more neutral terms like isosexuality or same-sex sexuality (Gowaty 1982). Meanwhile, anthropologists have proposed more specific terms to refer to particular non-Western homosexual activities. Anthropologist Gilbert Herdt (1994, xiv), for example, once suggested renaming the Sambia people’s ritualized homosexual activities as boy-inseminating practices. In chapter 2, we will discuss some of these proposals in more detail.

In recent years, this academic chorus has expanded to include some leading American news organizations and newspapers, whose stylebooks recommend substituting homosexual with gay for reasons not dissimilar to Kertbeny’s in the 1860s. In their view, the word homosexual should be avoided because it is derogatory and offensive (GLAAD 2016, 6). More particularly, it is a word whose clinical history and pejorative connotations are routinely exploited by anti-LGBTQ extremists to suggest that people attracted to the same sex are somehow diseased or psychologically and emotionally disordered (15). In short, we should avoid using homosexuality because of the negative connotations it acquired in the hands of nineteenth- and twentieth-century psychiatrists and anti-gay crusaders, and because it may predispose people to negative attitudes toward homosexuality and homosexuals (B. Smith et al. 2018).

We disagree with these recommendations, for reasons we explore here and in some of the chapters of this book.

First, any term can be used pejoratively or amelioratively. Kertbeny’s term has always been in the vocabulary of both advocates and opponents of homosexuality’s normality or moral value. Who decides, then, which connotation gets the upper hand? One popular answer to this question is that the decision is up to homosexuals themselves, as people have the right to be called whatever they choose. However, some philosophers have pointed out that this rule perhaps applies to proper names (Lady Gaga) and quasi-proper names of classes (African American) but not, or at least not evidently, to descriptive predicates, such as homosexual. The American philosopher Christopher Boorse (2010, 79) gives a personal example, noting how philosophy professors have no right to be called ‘persons of profundity,’ ‘moral paragons,’ ‘natural rulers,’ etc., no matter how much they might enjoy these descriptions. Importantly, minority activists have shown that terms can be reclaimed and that it is often easier to shift meanings than to replace words (Barnes 2016, 8). Queer, for example, was introduced in the English language as a derogatory term but is now embraced by the gay community and associated with pride and self-confidence (Berlant et al. 1994).

Second, changing our vocabulary may alleviate some people’s concerns in the short term, but in the long term, it produces a terminological volatility that is undesirable in scientific research. In the past, scientists have built a whole repertory of designations to refer to sexual activities between partners of the same sex, and each new designation increases the risk of obscuring interesting continuities and parallels among findings. We would rather not continue that tradition.

Third, none of the suggested alternative terms strike us as a worthy replacement for homosexuality. For one thing, they all lack its remarkable versatility. Many languages have some variant of the word homosexuality, which is not the case for gay, unless as a loan word. Many languages also have several lexical categories of the word: like gay, homosexual can act as both a noun and an adjective, but there is no gay noun equivalent for homosexuality. Perhaps most importantly, the word homosexuality can be put into action in diverse spheres of life. Most alternatives may work well in some contexts but not in others. While isosexuality could perhaps appeal to some zoologists, it would likely confuse nonprofessionals and annoy homosexuals. Conversely, gay may be appealing to many homosexuals and news organizations but not to scientists, who consider it too colloquial and too limited in scope.

For all these reasons, we have decided to stick to Kertbeny’s homosexuality and to his broad interpretation of the term. We do, however, readily acknowledge that this decision will not resolve all terminological problems. One issue with our definition of homosexuality is that it seems to simply shift the initial question (What is homosexuality?) to another, possibly even more difficult question: What is sexuality? What makes certain activities and physical states sexual? When two men are kissing, are they having sex? When one man is watching another man masturbate, are they having sex? And what about mental states? What turns a desire into a sexual desire, for example? These questions will have to wait until chapter 2, where we discuss the concept of sexuality in the context of homosexual behavior in nonhuman animals.

Another issue with our definition of homosexuality is that applying the term can result in confusion. Suppose, for example, that you are a man and that you are sexually attracted to Kim. Kim is a biological man who self-identifies as a man, but you believe Kim is a biological woman, and you are attracted to Kim because you believe Kim is a biological woman. Suppose that your attraction would be over as soon as you found out that Kim is a biological man. Is your attraction a homosexual attraction? Philosophers make a distinction between de dicto and de re desires or attitudes to address such issues. Based on a de dicto interpretation, your attraction to Kim is not homosexual. You are not attracted to Kim because he is a biological man or because Kim self-identifies as a man. Based on a de re interpretation, the attraction is homosexual because you are nonetheless attracted to a biological man who self-identifies as a man.

These issues may not be hugely important for the natural sciences that study homosexuality. However, the distinction between de re and de dicto can be important for the social sciences and the humanities, not because they are all profoundly interested in the metaphysics of sexual orientation but because they focus more on intra- and intercultural variation in sexual behavior and desire. Hence, they try to answer questions such as whether people feel attracted to the biological sex of other people or to the associated gender (Sandfort 2005), or even to something totally different, such as bodily characteristics (other than sex), personality types, social status, or age (for a lengthy discussion of this issue, see Stein 1999, 61–67).

What This Book Is Not About

Even though this book covers a lot of ground, it has its inevitable limitations, two of which deserve some attention.

Our first limitation is that we focus primarily on male homosexuality, both in humans and in other animals. This book is not about female homosexuality. There are two reasons for this focus.

First, there is simply more information about male homosexuality because both scientists and philosophers have always given it more attention than female homosexuality. The philosopher Arthur Schopenhauer (2018, 577) once sneered that, on reading Socrates’s orations, one would almost come to believe that women simply don’t exist. Part of the explanation for this bias is that most scientists and philosophers were men themselves, while women were often restricted from both professions. Another part has perhaps to do with the rather curious—but related—fact that male homosexuality has always kicked up more dust than its female version. According to Thomas Laqueur (1992, 53), Greek, Roman, and early Christian authors wrote much more about male homosexuality than about female homosexuality "because the immediate social and political consequences of sex between men